System Revolves Around Wetlands

Poke around where you will, it's hard to keep the eyes off the man-made wetlands at Cargill's Sugar Grove Farm north of Bowling Green, KY.Though the wetlands may be only a small part of this hog operation, they seem to capsulize the company's environmental philosophy in one 12-acre patch of cattails and reeds.For one thing, this wetlands system seems to actually work as designed. For another, there's

Roger Capshaw | Sep 15, 2000

Poke around where you will, it's hard to keep the eyes off the man-made wetlands at Cargill's Sugar Grove Farm north of Bowling Green, KY.

Though the wetlands may be only a small part of this hog operation, they seem to capsulize the company's environmental philosophy in one 12-acre patch of cattails and reeds.

For one thing, this wetlands system seems to actually work as designed. For another, there's something soothing about looking at it, watching the waterfowl in the open spots and other birds flitting from plant to plant. And there are turtles, too.

Up the hill sits a 1,600-sow nucleus farm built in 1992, a closed herd based on Dekalb genetics. Though it's technically a farrow-to-finish unit, barrows move out as feeder pigs. About 80% of the gilts, after performance evaluations, go to 16 Cargill multiplier herds. Most wind up in Arkansas. The rest go to Missouri.

Four cells make up the constructed wetlands area. The first cell covers five acres; the other three combine for seven acres. Water enters the wetlands system three ways: from a second stage lagoon, from a spring-fed pond or is recycled from cell four.

It's this blend of water that creates a healthy wetlands system. "It's a closed loop system. We blend it using the freshwater we create in the system," says Jeff Worstell, assistant general manager of Cargill Pork.

"It takes lots of management to turn wastewater into wetlands. Cattails can only handle 100 parts per million (ppm) of nitrogen. Higher levels will kill them. So you've got to know what the nitrate level is on the water running out of the second holding pond. It can be as high as 600 ppm. So we have to blend (fresh) water with it. That means, if it's 600 ppm, for every one part of lagoon water, we have to have five parts of fresh water to dilute into that."

Cargill contracts with Preacher Pumping Service to manage lagoons, wetlands and irrigation on cropland. That service assigned Bruce Uhls to the farm for the majority of his time.

"This is not just pumping manure. This is working with the environment," Uhls says. "We could see that wetlands on other farms generally were not working because they were overloading them with waste. We discovered that you have to really manage this thing."

It's key to have a flexible system, Uhls says. "If it's dry, we can pump water from the wetlands back through the system. If we get a big rain and the wetlands is full, we can pump water back into the lagoon. We've gotten the whole ball of wax here much more manageable, and it's a heck of a lot more environmentally friendly this way," he says.

Cattails do best in 2 ft. of water. Go deeper or shallower, and they'll struggle. So, it's important to be able to move water quickly, especially after a big rain. In addition to returning water to the first cell, it can go from the fourth cell to underground irrigation pipes, or to the second holding lagoon, where it helps dilute the system.

"By adding water that has, in a sense, gone through a treatment plant, it's like adding fresh water back into the system," Worstell says.

The levees surrounding the wetlands are 3 ft. high. Two-foot berms located about every 40 ft. channel the water. After entering the first cell, water takes 21 days of filtering through the system before exiting out the back of the fourth cell.

"Less than 2 ppm (nitrates) come out of cell No. 4. That's better than the state standard for drinking water," Worstell says.

The original wetlands idea came from PIC, the company that managed the farm before Cargill put its own team on-site. "When this farm was built, people were looking at alternatives. PIC already had one wetlands at its Dogwood Ridge Farm. The wetlands at Sugar Grove has worked out well for us. It's a big safety net. If there was a problem and we had to hold waste here, there's an awful lot of capacity before we'd need to be concerned about discharging into the environment," Worstell says.

But there's value beyond that. "We enjoy the wetlands," says Roger Capshaw, Sugar Grove Farm's manager. "It's nice to see the wetlands take what some call waste and turn it into water that frogs, birds and deer rely on. It makes a nice habitat. Those cattails and reeds do a great job of controlling odor. There's no smell associated with the water going through the wetlands."

Other folks like what they see at the wetlands, too. The farm now works with Western Kentucky University on its constructed wetlands near campus.

The college staff does all the farm's water samples, taken both upstream and downstream from the Sugar Grove Farm. They also monitor a stream running nearby, taking detailed fish counts in a shock-and-release program designed to see how the farm impacts water sources.

That impact should be zero, Worstell and Capshaw think.

Underground pipes carry effluent to a traveling gun irrigation system on the farm's 160 acres of cropland planted to corn, soybeans and hay. Cargill leases the property from the Green River Land Co., which tends the crops. The cropland, roads, wetlands, and even the lagoons are leased. According to the lease contract, the rest of the farm beyond the hog operation is available to handle effluent.

"We're very careful about putting the effluent on land. If the traveling gun system is running, it's supervised continuously. It's never unattended. If it's running, I never leave the site. I bring my dinner and plan to spend the day right there," Uhls says.

With an eye on eliminating runoff, they apply a half-inch of effluent water/acre at a time. "If you control it and watch it, that's better. I want to know where every drop of manure winds up," Uhls says.

The farmer, Craig Cohron, says the nitrogen in the effluent is worth $160/ton, based on the cost of anhydrous ammonia. "We're not using any other fertilizer. It's cut our cost per acre $50 to $60. It's little things like that that keep us in business," Cohron says.

The farm's automatic flushing system has an 1,100-gal. reservoir in each building.

Sugar Grove Farm's push to prevent spills includes a `manhole' for each hog building. These have a mercury float valve that tilts as effluent level rises. When it gets horizontal, the float kicks the entire system down.

In a monthly `house-keeping' audit, each check float is tested in sequence. "We believe in preventive maintenance. And we try to take every precaution we can," Worstell says.

Located about 3/4 mile off a county road, Sugar Grove Farm, sitting on 750 acres, is secluded and not easily seen by neighbors. The rolling wooded land here is picturesque but serves an additional purpose in filtering odors.

The woodland habitat supports a thriving deer and wild turkey population. Rabbits, squirrels and many birds also call this place home. The farm's primary wildlife program is to leave the woods untouched, giving animals the most natural habitat possible.

Most of the 14 employees live within a 3-mile radius of the farm. "We want to take care of it. It's serene. It's beautiful. The air is fresh. I enjoy the peace and tranquility of a place like this. My family and friends enjoy the hunting and fishing here," Capshaw says.

That's all the more reason to be good environmental stewards. "We have a heavy responsibility for environmental conservation. We have to be proactive. We have to be at the forefront. We have to be creative. It's not enough to do the minimum required. We have to go beyond that and enrich this land," according to the farm's award application.

"What's around us here is a precious gift from nature. I see environmental stewardship as the effort one takes to ensure the environment is unspoiled by human interference," Capshaw says.